Sulfur-doped Graphene Nanoribbons with a Sequence of Distinct Band Gaps

ORAL

Abstract

Unlike free-standing graphene, graphene nanoribbons (GNRs) can possess semiconducting band gap. However, achieving such control has been a major challenge in the fabrication of GNRs. Chevron-type GNRs were recently achieved by surface-assisted polymerization of pristine or N-substituted oligophenylene monomers. By mixing two different monomers, GNR heterojunctions can in principle be fabricated. Here we report fabrication and characterization of chevron-type GNRs by using sulfur-substituted oligophenylene monomers to achieve GNRs and related heterostructures for the first time. Importantly, our first-principles calculations show that the band gaps of GNRs can be tailored by different S configurations in cyclodehydrogenated isomers through debromination and intramolecular cyclodehydrogenation. This feature should open up new avenues to create multiple GNR heterojunctions by engineering the sulfur configurations. These predictions have been confirmed by Scanning Tunneling Microscopy (STM) and Scanning Tunneling Spectroscopy (STS). The unusual sequence of intraribbon heterojunctions may be useful for nanoscale optoelectronic applications based on quantum dots

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Authors

  • Shixuan Du

    Institute of Physics, Chinese Academy of Sciences, Institute of Physics, CAS

  • Yan-Fang Zhang

    Institute of Physics, Chinese Academy of Sciences

  • Yi Zhang

    Institute of Physics, Chinese Academy of Sciences

  • Reinhard Berger

    Max Planck Institute for Polymer Research

  • Xinliang Feng

    Technische Universität Dresden

  • Klaus Mullen

    Max Planck Institute for Polymer Research

  • Xiao Lin

    Institute of Physics, Chinese Academy of Sciences

  • Yuyang Zhang

    Vanderbilt University, Vanderbilt University, USA, Vanderbilt Univ, Department of Physics and Astronomy, Vanderbilt University

  • Sokrates T. Pantelides

    Vanderbilt University, Vanderbilt University, USA, Oak Ridge National Laboratory, USA, Vanderbilt University, Oak Ridge National Lab, Vanderbilt University, USA, Vanderbilt Univ., Department of Physics and Astronomy, Vanderbilt University, Department of Physics and Astronomy and Department of Electrical Engineering and Computer Science, Vanderbilt University

  • Hong-Jun Gao

    Institute of Physics, Chinese Academy of Sciences, Institute of Physics, CAS